There is less chance of being run over by a bus online, of contracting a serious communicable disease (computer viruses don't count), getting sunburned, falling off places or objects (other than your chair)...

Everything in life is "dangerous" when it interferes with the other good things you do until you live out of balance. That's why we need friends and church/social groups to keep track of us. We also see what un-balance does to others, and learn from their mistakes. Exercise is very good, but can easily get out of balance as seen at a Gymn.